From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Thu, 3 Nov 2022 04:37:56 +0000 (-0700)
Subject: cdt: squash -Wconversion warning
X-Git-Tag: 7.0.1~4^2~2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2ba71c805833c51d9490b3c8cf3bc43b7ad28ecd;p=graphviz

cdt: squash -Wconversion warning

This squashes the warning:

  dtstrhash.c:23:21: warning: conversion from ‘long int’ to ‘int’ may change
    value [-Wconversion]
     23 |                 n = s - (unsigned char*)args;
        |                     ^

This cast is mostly guaranteed safe by the inability to practically pass a
>INT_MAX length string into this function.
---

diff --git a/lib/cdt/dtstrhash.c b/lib/cdt/dtstrhash.c
index 41c99d3db..39f7089e4 100644
--- a/lib/cdt/dtstrhash.c
+++ b/lib/cdt/dtstrhash.c
@@ -1,4 +1,7 @@
+#include	<assert.h>
 #include	<cdt/dthdr.h>
+#include	<limits.h>
+#include	<string.h>
 
 /* Hashing a string into an unsigned integer.
 ** The basic method is to continuingly accumulate bytes and multiply
@@ -20,7 +23,8 @@ uint dtstrhash(uint h, void* args, int n)
 	if(n <= 0)
 	{	for(; *s != 0; s += s[1] ? 2 : 1)
 			h = (h + ((unsigned)s[0] << 8u) + (unsigned)s[1]) * DT_PRIME;
-		n = s - (unsigned char*)args;
+		assert(strlen(args) <= INT_MAX);
+		n = (int)(s - (unsigned char*)args);
 	}
 	else
 	{	unsigned char*	ends;